Adjustable focus eyeglasses with pivot adjustments

Abstract

A pair of adjustable focus eyeglasses having two lens units with at least one of the lens units having at least two lens elements. A mechanism is provided to pivot, about a pivot location outside each of the two lens elements, the position of at least one of the two lens elements relative to the other lens element in an angular direction generally perpendicular to a viewing direction. Specially designed surfaces are chosen such that small angular adjustments of the relative positions of the two lenses around a common pivot position in angular directions perpendicular or approximately perpendicular to a viewing direction results in changes in the combined focus of the two lenses of the lens unit. Preferred embodiments include two lens units with the lens system defining pairs of adjustable focus eyeglasses.

Description

[0001]This application is a continuation in part of U.S. patent applications, Ser. No. 11 / 085,436 filed Mar. 21, 2005 now U.S. Pat. No. 7,372,646 Ser. No. 11 / 243,944 filed Oct. 5, 2005 now U.S. Pat. No. 7,232,217 and Ser. No. 11 / 387,023 filed Mar. 21, 2006 now U.S. Pat. No. 7,338,159. This invention relates to eyeglasses and in particular to adjustable focus eyeglasses.BACKGROUND OF THE INVENTIONNearsightedness and Farsightedness[0002]Nearsightedness is a condition of the eye in which distance objects cannot be focused on the retina and farsightedness is a condition of the eye in which near objects cannot be focused on the retina. These conditions are normally corrected by spectacle lenses having a power needed to correct the eye's focus error.Astigmatism[0003]Astigmatism is a condition of the eye caused by an irregular curvature of an eye surface, usually the front surface. It can be corrected by a spectacle lens in which at least one surface has a different curvature in different ...

AI Technical Summary

Benefits of technology

[0027]In preferred embodiments a sweet spot is provided in the region of the lenses centered directly in front of the wearer's eyes (when looking straight ahead), and within a certain cone angle, by precise application of the above equations in the sweet spot, but choosing a different lens design outside the sweet spot. This can have the effect of minimizing thickness differences at the edges of the lenses.Prescription Surfaces

Problems solved by technology

The two lenses do not perfectly cancel, but as long as the power is fairly weak (i.e., less than about 5 diopters), the human eye does not detect the residual aberration.

After age 40 in most people (and by age 45 in virtually all people) a clear, comfortable focus at a near distance becomes more difficult with eyes that see clearly at a far distance.

Unless one is nearsighted, it is not possible to focus objects (such as a printed page) clearly at even an arm's length distance.

Bifocals, trifocal and continuous focus glasses all have their problems as is well known by the people who wear them, and the automatic focus glasses have not been successful in solving the problems.

Surgery can correct vision problems in many cases, but eye surgery is expensive and many people who can afford eye surgery, prefer to avoid it.

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